lan91c95 Standard Microsystems Corp., lan91c95 Datasheet - Page 87

• Manufacturer Part Number: lan91c95
• Description: Isa/pcmcia Full Duplex Single-chip Ethernet And Modem Controller With Ram
• Manufacturer: Standard Microsystems Corp.

ISR
Save Bank Select & Address
Ptr Registers
Mask 91C94 Interrupts
Read Interrupt Register
No
Y es
RX INTR?
Y es
TX INTR?
Call TX INTR or TXEMPTY
INTR
No
Call RXINTR
Get Next TX
ALLOC INTR?
Packet
No
Y es
Available for
Transmission?
Y es
No
Write Allocated Pkt # into
Packet Number Reg.
Call ALLOCATE
Write Ad Ptr Reg. & Copy Data
& Source Address
Enqueue Packet
EPH INTR?
Y es
No
Set "Ready for Packet" Flag
Restore Address Pointer &
Call EPH INTR
Bank Select Registers
Return Buffers to Upper Layer
Unmask 91C94 Interrupts
Disable Allocation Interrupt
Mask
Exit ISR
FIGURE 10 - ETHERNET INTERRUPT SERVICE ROUTINE
87